Molten metal sampling apparatus



May 30, 1967 P. 1.. JACKSON MOLTEN METAL SAMPLING APPARATUS 2Sheets-Sheet 1 Filed July 29, 1965 PA UL LJAcka/v INVENTOR y-5 .1967P.|..JAK$Q- 3,321 1 MOLTEN METAL SAMPLING APPARATUS Filed July 29, 19652 Sheets$heet 2 INVENTOR ATTORNEYS PAUL LJACKSON United States Patent 3321,978 MOLTEN METAL SAMPLING APPARATUS Paul L. Jackson, Dearborn,Mich., assiguor to Ford Motor Company, Dearborn, Mich., a corporation ofDelaware Filed July 29, 1965, Ser. No. 475,739 18 Claims. (Cl. 73425.4)

ABSTRACT OF THE DISCLOSURE This disclosure describes apparatus forobtaining solidified samples of molten metal such as steel. A metal moldpositioned in an insulating jacket has a frangible collar surroundingthe upper portion of the mold. A buoyant cover seals the opening of themold until the mold is under the slag layer and a U-bolt assemblyretaining the cover in place then melts to release the cover. The coverfloats away carrying with it any adhered slag and permitting the moldcavity to fill with a sample accurately representative of the moltenmetal. A washer of insulating material can be interposed between cover,mold and U- bolt to prevent the molten metal from welding these itemstogether before a sample has filled the mold.

After the apparatus has been removed from the molten metal, thefrangible collar is shattered to facilitate easy removal of the samplefrom the mold. The apparatus is particularly useful in obtaining samplesof molten steel from which the oxygen content of the steel can bedetermined accurately.

This invention concerns an apparatus and a process for obtaining asolidified sample of molten metal. In particular, this invention isuseful in obtaining solidified samples of molten steel from which theoxygen content -of the steel can be accurately determined.

Spoon sampling of molten metal by taking a slagged spoon of metal fromthe furnace, skimming off the slag, immediately killing the sample withaluminum wire, and solidifying the killed sample produces inaccurateresults because of oxidation of the sample by the slag and thesurrounding air. Improvements in spoon sampling included the use of amold having a cover to prevent entry of slag into the sample when themold is inserted through the slag layer. These molds were made withsufficient mass to absorb the heat necessary to solidify the samplewhile immersed in the molten metal. With these molds samples could betaken and solidified without exposure to air. Difficulties involved inthe use of these molds included adherence of slag to the cover duringinsertion through the slag layer with subsequent entry of slag into thesample, removal of the solidified sample from the mold and preparationof the solidified sample for analysis.

Apparatus provided by this invention for obtaining a solidified sampleofmolten metal comprises a mold open at one end and having a samplecavity, the exterior of said mold having a lower portion and an upperportion, said mold being capable of absorbing heat sufficient tosubstantially solidify molten metal filling-said cavity, a heatinsulating sleeve surrounding the lower portion of the mold, a frangiblecollar surrounding at least part of the upper portion of the mold; acover for the open end of the mold, said cover comprising a sealingmember associated with a buoyant member, said sealing membersubstantially sealing the open end of the mold; means for temporarilyretaining the cover in position, said retaining means being capable ofreleasing the cover after submergence in the molten metal; and means forsubmerging the mold into and removing the mold from the molten metal.Reproducibility of oxygen content determinations of molten steel usingapparatus of this invention averages about 0.003% as compared withvariations of nearly .02% when using the spoon sampling molds of theprior art. Many of the difficulties encountered when using spoonsampling molds of the prior art, including those listed above, are alsoovercome when using apparatus of this invention.

FIGURE 1 of the drawings is an exploded view of the sampling apparatusof this invention;

FIGURE 2 is an assembly view of this apparatus;

FIGURE 3 shows the apparatus after removal from the molten metal with asolidified sample;

FIGURE 4 is a partially exploded cross section of the apparatus shown inFIGURE 3.

FIGURE 1 shows a mold 10 having an inwardly tapered sample cavity 12 andan outwardly tapered upper portion 16 which simplify removal of thesolidified sample, especially when the mold is of unit construction. Themass of mold 10 is suflicient to absorb enough heat from the sample ofmolten metal eventually filling cavity 12 to substantially solidify thatmetal while the apparatus of this invention is submerged in the moltenmetal. Materials of construction for mold 10 are preferably capable ofconducting heat away from the molten metal filling the mold cavity withsufficient rapidity to prevent substantial adherence of the sample aftersolidification to the mold. Copper, silver, or alloys, are preferredmaterials of construction for mold 10 because of high heatconductivities, high melting points and decreased tendency to weld tothe molten steel sample. Copper, of course, is more economical to usethan silver. If desired, upper portion 16 can have a straight lowersection 17. Mold 10 is preferably of unit construction but can be of thesplit type; The lower portion 14 of mold 10 is surrounded by a heatinsulating sleeve 20 which prevents substantial loss of the heatcapacity of mold 10 to surrounding molten metal. Ceramic coated steel 42is preferably used as sleeve 20 because of excellent strength andinsulating properties.

Surrounding part of the length of upper portion 16 is a frangible collar22. Collar 22 is preferably made of ceramic materials, such as zircon,to provide additional heat insulation. If desired, additional strengthcan be imparted to collar 22 by wrapping collar 22 with wire 23. Bycovering the joint 13 between sleeve 20 and upper portion 16 with collar22, entry of molten metal into the .space between sleeve 20 and thelower portion 14 of molten metal being sampled. Wood is preferred forblock 26 when sampling molten steel because of economy, ease offabrication and efiicient operation. Ceramics or other materials havingbuoyancy in the molten metal being sampled can also be used. Metal plate25 substantially seals the open end of mold 10 to prevent slag fromentering the mold cavity 12. A recessed area 27 can be provided incover-24 if desired;

U-bolt assembly 28 fits over cover 24 and handle head 32 as shown inFIGURE 2, thereby temporarily retaining cover 24 in position. U-bolt 29is preferably of a material vmelting at a temperature less than thetemperature of the molten metal and thereby capable of releasing cover24 after submergence in the molten metal. When sampling molten steel,U-bolt 29 is preferably a inch steel rod and metal plate 25 ispreferably at least about 0.060 inch thick to prevent premature fillingof mold cavity 12.

Provided for submerging the mold 10 into and removing the mold from themolten metal is pipe 44 attached by means of bolt 46 to steel bar 47.Bar 47 is attached in turn to bolt assembly 48, thereby forming aU-shaped assembly to allow submerging of mold 10 in a substantiallyupright position. Surrounding this U-shaped assembly of pipe 44, bolt46, bar 47, and bolt assembly 48, is an insulating fibrous material 50coated with a ceramic insulating coating 52. A typical fibrous materialis fibrous aluminum silicate. Aluminum silicate can also be used as theinsulating coating. Mold 10 is threadably attached to bolt assembly 48with washers 36 interposed to prevent fouling of the threads by moltenmetal. Washers 36 can also be made of fibrous aluminum silicate. Handleassemblies made in this manner can be used several times toobtainsamples of molten steel before requiring patching.

A solidified sample of molten metal is obtained according tothisinvention by submerging the apparatus of this invention in themolten metal; holding apparatus submerged until the cover 24 is releasedallowing the cavity 12 to substantially fill with molten metal; removingthe a 'mold from the molten metal; breaking frangible collar 22 andremoving sample 40 from the mold cavity 12. The frangible nature ofcollar 22 is useful in promoting rapid removal of samples from the moldcavity. After removal of collar 22 the solidified sample 40 ordinarilyhas a mushroom-shaped head 41 which can be gripped with pliers to removesample 40 from cavity 12. Sample 40 is of the pin type from whichsamples for analysis can be easily machined. By designing retainingmeans 28 to release cover 24 after a certain immersion time, samplesfrom various depths of submergence can be accurately taken withapparatus of this invention.

Means for preventing welding of cover 24 to the mold assembly, wherebycavity 12 is not properly filled with a sample, are desirablein'apparatus of this invention when sampling certainmolten metals. Thismeans can comprise a washer 34 of an insulating material such ascardboard or fibrous aluminum silicate interposed be- 'tween the cover24 and collar 22 and between the U-bolt 29and collar 22. When samplingsteels, a sm-all'ball of aluminum wire 38 can be placed in the mouth' ofmold cavity 12 to kill the steel.

What'is claimed is: e 1. Apparatus for obtaining a solidified sample ofmolten metal which comprises 'a mold open at one end and having a samplecavity, the exterior of said mold having a lower portion and an upperportion, said mold being capable of absorbing heat sufficient tosubstantially solidify molten metal filling said cavity, a heatinsulating sleeve surrounding the lower portion of the mold,

a frangible collar surrounding at least part of the upper portion of themold, r a buoyant cover for the open end of the mold,

means for temporarily retaining the cover in position, said retainingmeans being capable of releasing the cover after submergence in themolten metal, and

. means'for submerging the mold into and removing the mold from themolten metal. 7 V 2. The apparatus of claim 1 in which the mold has aninwardly tapered cavity. I

3. The apparatus of claim 2 in which the mold is of unit construction.

' 4. The apparatusof claim 3 in which the mold has an outwardly taperedupper portion.

5. The apparatus of claim 4 which has means for preventing the weldingof the cover to the mold.

'6. The apparatus of claim. 5 in which the means for preventingweldingof the cover to the mold comprises a washer of insulating materialinterposed between the cover and the collar and between the retainingmeans a and the collar.

7. The apparatus of claim 6 in which the mold is capable of conductingheat away from the molten metal filling the mold cavity with sulficientrapidity to prevent substantial adhesion of the solidified sample to themold.

8. The apparatus of claim 7 in which the mold is essentially copper,silver or alloys thereof.

9. The apparatus of claim 8 in which the buoyant cover comprises a woodblock.

10. The apparatus of claim 1 in which the mold is capable of conductingheat away from the molten metal filling the mold cavity With sufficientrapidity to prevent substantial welding of the metal raftersolidification to the mold.

11. The apparatus of claim 1 which has means for preventing welding ofthe cover to the mold.

12. The apparatus of claim 1 in which the mold has anoutwardly taperedupper portion.

13. The apparatus of claim 1 in which the cover comprises a wood block.

14. The apparatus of claim 1 in which the mold is" essentially copper,silver or alloys thereof.

15. Apparatus for obtaining a solidified sample of molten steel whichcomprises a mold open at one end and having a sample cavity, theexterior of said mold having a lower portion and an upper portion, saidmold being capable of absorbing heat sufiicient to substantiallysolidify molten metal filling said cavity,

a heat insulating sleeve surrounding the lower portion of the mold,

a frangible collar surrounding at least part of the upper 1 16.Apparatus for obtaining a solidified, sample of' molten steel whichcomprises a mold open at one end and having a sample cavity, a theexterior of said mold having a lower portion and.

an upper portion, said mold being capable of absorbing heat sufiicientto substantially solidify molten metal filling said cavity, a

a heat insulating sleeve surrounding the lower portionof the mold,

a frangible collar surrounding at least part of the upper portion of themold,

-=a buoyant cover for the open end of the mold,

means for temporarily retaining the cover in position,

said retaining means being capable of releasing the cover aftersubmergence in the molten metal, and

means for submerging the mold into and removing the mold from the moltenmetal.

17. Apparatus for obtaining a solidified sample of' molten steel whichcomprises a mold open at one end and having a sample cavity,

the exterior of said mold having a lower portion and an upper portion,said moldbeing capable of absorbing heat sufficient to substantiallysolidify molten metal filling said cavity,

a .fran'gible collar surrounding at least part of the upper portion ofthe mold,

a cover for the open end of the mold, said cover cornprising a sealingmember attached to a-buoyant memher, said sealing member substantiallysealing the open end of the mold, V means for temporarily retaining thecover in position,

said retaining means being capable of releasing the cover aftersubmergence in the molten metal, and

means for submerging the mold into and removing the mold from'the moltenmetal.

buoyant 18. Apparatus for obtaining a solidified sample of molten steelwhich comprises a mold open at one end and having a sample cavity, theexterior of said mold having a lower portion and an upper portion, saidmold being capable of 5 absorbing heat suflicient to substantiallysolidify molten metal filling said cavity,

a frangible collar surrounding at least part of the upper portion of themold,

a buoyant cover for the open end of the mold,

means for temporarily retaining the cover in position, said retainingmeans being capable of releasing the cover after submergence in themolten metal, and

means for submerging the mold into and removing the mold from the moltenmetal.

References Cited UNITED STATES PATENTS 2,970,350 2/ 1961 Feichinger73-425.6 3,221,559 12/1965 Miller et al. 73425.4

DAVID SCHONBERG, Primary Examiner.

0 LoUIs R. PRINCE, Examiner.

S. C. SWISHER, Assistalnt Examiner.

18. APPARATUS FOR OBTAINING A SOLIDIFIED SAMPLE COMPRISES MOLTEN STEELWHICH COMPRISES A MOLD OPEN AT ONE END AND HAVING A SAMPLE CAVITY, THEEXTERIOR OF SAID MOLD HAVING A LOWER PORTION AND AN UPPER PORTION, SAIDMOLD BEING CAPABLE OF ABSORBING HEAT SUFFICIENT TO SUBSTANTIALLYSOLIDIFY MOLTEN METAL FILLING SAID CAVITY, A FRANGIBLE COLLARSURROUNDING AT LEAST PART OF THE UPPER PORTION OF THE MOLD, ABUOYANTCOVER FOR THE OPEN END OF THE MOLD, MEANS FOR TEMPORARILY RETAINING THECOVER IN POSITION, SAID RETAINING MEANS BEING CAPABLE OF RELEASING THECOVER AFTER SUBMERGENCE IN THE MOLTEN METAL, AND MEANS FOR SUBMERGINGTHE MOLD INTO AND REMOVING THE MOLD FROM THE MOLTEN METAL.